An engagement ring is lifetime commitment, and not one to be taken lightly—not that we ever take diamonds lightly. Tom Burstein is a senior jewelry specialist for Christie's International Jewelry Department and was a key player in the record-breaking sale of the collection of a woman whose very name conjures images of all things that sparkle—Elizabeth Taylor. BAZAAR asked Burstein, whose CV also includes serving as vice president and head of U.S. retail and estate jewelry for Harry Winston, among other blingy feats, to break down the process of investing in an estate piece for that all-important ring. (Feel free to forward this article on to any gentleman seeking guidance.)

Harper's Bazaar: Where is the best place to start if you want an estate engagement ring?

Tom Burstein: The first step one should take is to establish a budget. The cost of an engagement ring can vary greatly depending on the type of center stone, and its size and quality. At the same time, it is helpful to determine a general style of the ring and cut of the center stone. Great ideas can be found looking through auction catalogues and visiting websites that cater to estate jewelry. With a good idea of style and budget, a bridal specialist will be able to better assist the purchaser with choosing the perfect ring.

TB: When buying vintage estate jewelry it is always best to buy a ring that is original in all its parts. That is part of its beauty. Sometimes, however, a diamond has been handed down for generations and it can be very sentimental to create a beautiful ring by matching an older-cut stone to a vintage setting. I do not recommend pairing a modern-cut stone to a vintage setting as the ring could lose much of its charm and beauty.

HB:Does changing the setting of an estate piece at all de-value it?

TB: It depends, in most cases the mounting — whether it be vintage or contemporary—makes up for only a small amount of the actual dollar value of the ring. Like any vintage object, however, it does lose some value when it no longer remains in its original state.

HB:What are the cons of estate pieces? Pros?

TB: The main downside of buying is an estate piece maybe issues with condition. A ring that is 50 or 100 years old may have seen considerable wear which may now affect its durability and appeal. As long as you have a well-educated and reliable specialist assisting you one can easily find an estate jewel that is in very good condition. The benefits are too many to list. The type of estate ring chosen says a lot about a couple's taste and values. An estate ring can symbolize the uniqueness and sincerity of a couple's love for each other while also being a standout from other engagement rings among their contemporaries.

HB:What's the best way to make sure you're getting a legitimate piece?

TB: Work with a reputable and established jeweler or auction house. Engagement ring shoppers love to visit us at Christie's as they not only get expert advice, but they get a great variety of estate rings from which to choose—many of them with great stories attached.

HB:Is the price generally higher than a new diamond of the same size?

TB: Price is always relative and mostly depends on the size and quality of the diamond, regardless of whether it is a diamond that was cut 100 years ago or one that was cut in recent years. Cutting techniques have been perfected over the years to maximize a diamond's fire and brilliance, which may result in a higher price. On the other hand, older cuts such as an antique cushion-cut or pear-shaped are highly sought after and can bring a greater price than a similar modern cut stone.

TB: What a buyer can expect is really a function of their budget along with the size and quality for which they are looking. For some people size is the most important criteria, in which case they may sacrifice some quality to obtain the larger size. Others may prefer a higher quality stone in a smaller size in a price within their budget.

HB:What are some of the popular eras in estate jewelry now?

TB: People love the delicate micropave work in settings from the early 20th Century, as well as more geometric designs from the 1930s and even more bold settings in yellow gold and colored stones from the 1960s and 70s.

HB:What should buyers be wary of?

TB: Buyers have to make sure they are getting exactly what they pay for. In other words, diamonds and other precious gemstones are a big investment and they are priced based on size and overall quality. Make sure the center stone is accompanied by a gemological report which accounts for the technical qualitative details of the stone.

HB:We can't all get Elizabeth Taylor's jewelry, but can someone know the progeny of their ring?

TB: Many times in our auction catalogues a ring will be designated in some fashion, such as Property of a Prominent New York Family or if the owner is a known figure it may be designated under their name. Part of the intrigue when purchasing estate jewelry is not knowing the exact story behind the jewel but to imagine all the great stories and travels it has been on over the years.